The geocentric theory held that the Earth was the center of the universe. Its main exponent was the Egyptian Ptolemy, in his Almagest. It described the movement of planets and stars, through a complicated series of spheres which were suspended in all these stars. This work is the second century. It was in effect until the sixteenth century.
Then came the heliocentric theory, which held that the Sun was the center of the universe, and the other stars revolved in orbits around it, including our Earth.
Nicolaus Copernicus was the leading exponent of heliocentrism, when he published his work De Revolutionibus Orbium Coelestium in 1543.
